GABA:

GABA

GABA:

GABA GABA functions as an inhibitory transmitter in many different CNS pathways. About 20% of CNS neurons are GABAergic; most are short interneurons, but long GABAergic tracts run to the cerebellum and striatum. GABA serves as a transmitter at about 30% of all the synapses in the CNS.

Monoamine Transmitters:

Noradrenaline:

Noradrenaline

Noradrenaline Synthesis:

Noradrenaline Synthesis The basic processes responsible for the synthesis, storage, release and reuptake of noradrenaline are the same in the brain as in the periphery and the same types of adrenoceptor are also found in pre- and postsynaptic locations in the brain.

Noradrenaline Function:

Noradrenaline Function The actions of noradrenaline are mainly inhibitory (β-receptors), but some are excitatory (α- or β-receptors). Noradrenergic transmission functions in the 'arousal' system, controlling wakefulness and alertness blood pressure regulation control of mood (functional deficiency contributing to depression).

PowerPoint Presentation:

Noradrenaline Pathway:

Noradrenaline Pathway The cell bodies of noradrenergic neurons occur in small clusters in the pons and medulla, and they send extensively branching axons to many other parts of the brain and spinal cord The most prominent cluster is the locus coeruleus (LC) , located in the pons. descending control of pain pathways

Dopamine Synthesis :

Dopamine Metabolism:

Dopamine Metabolism

Dopamine Distribution:

Dopamine Distribution Distribution of dopamine in the brain is more restricted than that of noradrenaline Dopamine is most abundant in the corpus striatum , a part of the extrapyramidal motor system concerned with the coordination of movement

Vomiting:

Vomiting Dopaminergic neurons have a role in the production of nausea and vomiting. N early all dopamine receptor agonists (e.g. bromocriptine ) and other drugs that increase dopamine release in the brain (e.g. levodopa) cause nausea and vomiting as side effects, Dopamine antagonists (e.g. phenothiazines , metoclopramide) have antiemetic activity. D2 receptors occur in the area of the medulla (chemoreceptor trigger zone) associated with the initiation of vomiting and are assumed to mediate this effect.

Serotonin:

Serotonin

Serotonin (5-HT):

Serotonin (5-HT) Lysergic acid diethylamide (LSD) , a drug known to be a powerful hallucinogen acted as a 5-HT antagonist on peripheral tissues, and suggested that its central effects might also be related to this action . 5HT 2A 5-HT is mainly found in 99% in gut, but1 % in brain important. Selective serotonin reuptake inhibitors constitute an important group of antidepressant drugs.

5-HT Synthesis:

5-Hydroxytryptamine pathways :

5-Hydroxytryptamine pathways

Serotonin Pathways:

Serotonin Pathways 5-HT neurons are concentrated in the midline raphe nuclei in the pons and medulla, Projecting diffusely to the cortex Limbic system H ypothalamus Spinal cord S imilar to the noradrenergic projections.